Energization of the combustible mixture in an internal combustion engine

ABSTRACT

Engine vacuum is used to draw a stream of air into the intake system. Some of the energy of this air stream is converted to pressure waves. The flow rate of the air stream is controlled responsive to the mode of engine operation to provide the proper amount of pressure wave energy.

1969, abandoned, and a continuation-in-part of Ser. No. 13,977, Feb. 25,1970, abandoned, and a con tinuationin-part of Ser, No. 17,484, March 9,1970, Pat. No. 3,613,722, and a continuation-in-part of Ser. No. 82,771,Oct. 21, 1970, abandoned, and a continuation-in-part 0f Ser. No. 1 11,995, Feb. 2, 1971.

US. Cl. ..123/l42, 123/119 A, 123/119 B, 123/52 M, 239/1, 239/4, 261/1Int. Cl...F02m 27/00, F02m 27/08, F02m 29/00 FieldofSearch ..123/1, 119R, 119 E, 123/142,198 E, 52 M, 32 E1,119 A, 119 B; 261/1; 239/4, 102

O 1 United States Patent 0 1 1 3,739,169 Hughes May 1, 1973 ENERGIZATIONOF THE COMBUSTIBLE MIXTURE IN AN er ces Cited INTERNAL COMBUSTION ENGINEUNITED STATES PATENTS [75] Inventor: g l g i Ronmg 1,939,302 12/1933Heaney ..261 1 8 a 2,436,570 2/1948 Hancock. ..123/19s E [73] Assignee:Energy Sciences Incorporated, E] 2,532,554 12/1950 Joeck ..123/198 E UXSegundo Calif 2,704,535 3 1955 Magui et 41.. ....123 19s E ux 2,732,8351 1956 Hundt ..123/19s E ux [22] Filed: July 1,1971 2,745,372 5/1956Chertoff .....123/119 E ux 2,791,990 5 1957 Grieb 123 52 M 1 1 pp158,915 2,791,994 5/1957 Grieb 123/198 E UX 2,908,443 10 1959 Fruengel..239 102 Related Appllcatlon Data 3,206,124 9/1965 Drayer et al......239 4 x [63] continuafimimpm of No. 855,321 Sept. 4, 3,554,4431/1971 Hughes ..239/4 Primary Examiner-A1 Lawrence SmithAttorney-Christie, Parker & Hale [57] ABSTRACT Engine vacuum is used todraw a stream of air into the intake system. Some of the energy of thisair stream is converted to pressure waves. The flow rate of the airstream is controlled responsive to the mode of engine operation toprovide the proper amount of pressure wave energy.

10 Claims, 34 Drawing Figures Patented May 1, 1973 3,730,160

10 Sheets-Sheet 1 Patented May 1, 1973 10 Sheets-Sheet 6 FIGI] FIG l5FIG l6 10 Sheets-Sheet 4 Patented May 1, 1973 3,730,160

10 Sheets-Sheet 5 INVEN TOR. fl/i/W/M/AZ #464455 NH N MINI mm lllll llln27 Patented May 1, 1973* 3,730,160

10 Sheets-Sheet 7 'Pqtented May l, 1973 10 Sheets-Sheet B Patented May1, 1973 3,730,160

10 Sheets-Sheet 9 EN ERGIZATION OF THE COMBUSTIBLE MIXTURE IN ANINTERNAL COMBUSTION ENGINE CROSS REFERENCE TO RELATED APPLICATIONS Thisis a continuation-in-part of my following copending applications, whichare incorporated herein by reference: Ser. No. 855,321, filed Sept. 4,1969 now abandoned; Ser. No. 13,977, filed Feb. 25, 1970 now abandoned;Ser. No. 17,484, filed Mar. 9, 1970 now US. Pat. No. 3,613,722; Ser. No.82,771, filedOct. 21, 1970 now abandoned; and Ser. No. 1 11,995, filedFeb. 2, 1971.

BACKGROUND OF THE INVENTION This invention relates to the energizationof the combustible mixture in an internal combustion engine and,

can be cut by increasing the air-to-fuel ratio up to the point at whichcomplete combustion takes place; however, the corresponding increase inthe heat produced in the combustion cylinders raises the level of theoxides of nitrogen. By increasing the air-to-fuel ratio beyond the pointof complete combustion, the level of the oxides of nitrogen dropsbecause the additional air cools the combustion cylinders; however, theengine efficiency is impaired by theleanness of the combustible mixture.

The two principle sourcesof automobile pollution are crankcase emissionsand exhaust emissions. Crankcase emissions, which consist of oildroplets and unburned fuel in the form of blowby gases, have beenreduced by returning these emissions in a mixture with air to the intakesystem of the automobile engine for combustion. The'standard process forreturning crankcase emissions to the intake system is called positivecrankcase ventilation (PCV). In a PCV system, one conduit couples theinlet of the carburetor to the crankcase manifold and a second conduitcouples the crankcase manifold to the outlet of the carburetor, therebycarrying partially burned products of combustion out of the crankcasemanifold for recom bustion with the combustible mixture formed in thecarburetor. A snap action pressure responsive valve in the secondconduit, which bleeds a small amount of the returned mixture to theintake system during idle and cruise, opens fully during acceleration.To some extent,

PCV reduces the hydrocarbons and carbon monoxide, but it may in factincrease the oxides of nitrogen produced by the engine. In fact, some ofthe emissions returned by the PCV system for combustion may even-'tually find their way into the atmosphere through the exhaust system ofthe engine. Furthenfrequent maintenance is required in order to preventthe PCVvalve from clogging in the closed position, in which case the PCVsystem becomes ineffective.

To combat exhaust emissions, either the efficiency of the combustionmust be increased or the incompletely burned exhaust gases must beconsumed by an afterburner or the like.

Some attempts have been made to atomize the gasoline while in thecarburetor so as to achieve more complete burning of the combustiblemixture in the en gine and thereby to reduce the pollutants produced bythe engine. One class of atomizer, of which a spinning disc is typical,employs the engine itself as a source of power to atomize the gasoline.These atomizers are in general so inefficient that in order to atomizethe gasoline effectively a substantial portion of the available enginepower is dissipated. Therefore, engine performance is unduly impaired.Another class of atomizer employs an electrically powered ultrasonicgenerator, of which a piezoelectric crystal is typitEal. In order toatomize the gasoline effectively it must be brought into contact withthe surface of the crystal, because of the sharp attenuation of thegenerated ultrasonic waves. This technique does not take any measures toensure that the gasoline is maintained in an atomized state until thetime of combustion.

Fuel injection has also been employed to reduce automobile pollutants.The equipment needed to achieve significant results is very complex andexpensive due to the precise timing required to practice fuel injection.

SUMMARY OF THE INVENTION According to the invention, the: vacuum createdby the operation of an engine is used as the source of energy forgenerating pressure waves. The engine vacuum draws a stream of fluidinto the intake system from a fluid source such as the atmosphere. Someof the energy of this fluid stream is converted. into pressure wavesthat propagate throughout the intake system of the engine.

The flow rate of the fluid stream is controlled as a function of theengine mode of operation, e.g., more fluid energy is supplied duringacceleration than during idle. The control of the amount of pressurewave energy is most simply accomplished by a pressure responsive valvethrough which the fluid stream passes into theintake manifold. The valveis open during acceleration and closed except for a bleed orifice duringidle, deceleration, or cruise. Further control of the amount of pressurewave energy can be effected by employing an energy conversion devicethat tendsto pass fluid at a flow rate that is directly related to theabsolute pressure. Thus, as the absolute pressure in the intake manifolddrops, i.e., the vacuum becomes higher, the flow rate and thus theenergy conversion decreases.

BRIEF DESCRIPTION or THE DRAWINGS The features of numerous specificembodiments of the best mode contemplated of carrying out the inventionare illustrated in the drawings, in which:

FIG. 1 is an elevational view, partially broken away, of a conventionalautomobilecarburetor, including embodiments of the present invention;

FIG. 2 is a sectional viewof the apparatus of FIG. 1, along line 2-2thereof, with portions broken away, and the venturi and attached cellshown in elevation;

FIGS. 3 and 4 are enlarged perspective views of a nozzle employed in theembodiments of FIG. 1;

FIG. 5 is an enlarged elevational view, partially broken away, of theidle air assembly of FIG. 1;

FIG. 6 is an end view of a portion of the apparatus of FIG. 1,disconnected from the carburetor;

FIG. 7 is a sectional view of the apparatus of FIG. 6, along line 7-7thereof;

FIG. 8 is an elevational view, partially broken away, of a carburetoridentical to that of FIG. 1, except including different embodiments ofthe present invention;

FIG. 9 is an enlarged sectional view of a portion of the apparatus ofFIG. 8;

FIG. 10 is an enlarged elevational view, partially broken away, of theidle air assembly of FIG. 8;

FIGS. 11 and 12 constitute an elevational view, partially broken away,of a carburetor, identical to that of FIG. 1, except including,partially assembled thereto in FIG. 11, and attached thereto through abroken-away connector in FIG. 12, still other embodiments of the presentinvention;

FIG. 13 is an end view of the embodiment of FIG. 1 l, and pertinentportions of the carburetor;

FIG. 14 is a sectional view of a portion of the embodiment of FIG. 13,showing the construction of the adapter and one of the four identicalcells attached thereto;

FIG. 15 is a view like FIG. 14, showing a variant cell construction;

FIG. 16 is a sectional view of the embodiment of FIG. 12, along line16-16 thereof;

FIG. 17 is a schematic diagram of a PCV system of an internal combustionengine, which illustrates the introduction of pressure wave energy intothe intake system of an internal combustion engine through a PCV line;

FIG. 18 is a schematic diagram of the intake system of an internalcombustion engine, which illustrates several ways in which sonic waveenergy is simultaneously introduced; I

FIGS. 19 and 20 are perspective views of alternative apparatus forgenerating sonic waves;

FIGS. 21 and 22 are, respectively, front and side sectional views of adifferent type of apparatus for generating sonic waves;

FIG. 23 is a side sectional view of an alternative arrangement of theapparatus of FIGS. 21 and 22;

FIG. 24 is a top sectional view of apparatus for introducing sonic wavesinto the stream of air flowing into the carburetor;

FIG. 25 is a side sectional view of apparatus for introducing sonicwaves into the stream of air flowing from the carburetor. to the intakemanifold;

FIG. 26 is a top sectional view of the apparatus of FIG. 25;

FIG. 27 is a schematic block diagram depicting three ways in whichpressure wave energy is simultaneously inroduced into an intake system;

FIG. 28 is a side sectional elevation view of ap paratus for injectingsonic wave energy directly into a combustion cylinder at its intakevalve;

FIG. 29 is a graph of the effective orifice area of a two state airmanagement valve as a function of the engine vacuum;

FIG. 30 is a schematic block diagram of a more effective air managementsystem than a two-state valve;

FIG. 31 is a graph of the effective orifice area of the air managementsystem of FIG. 30 as a function of engine operation;

FIG. 32 is a schematic block diagram of a still more effective airmanagement system;

FIG. 33 is a graph of the air flow rate through the air managementsystem of FIG. 32 as a function of engine operation; and

FIG. 34 is a schematic block diagram of an alterna tive to the airmanagement system of FIG. 30.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS As used in thisspecification, the term shock waves means periodic positive pressurepulses that are predominately unipolar, i.e., the pressure at a givenpoint in space pulsates between ambient pressure and a pressure higherthan ambient pressure so compression of the fluid molecules repeatedlyoccurs, although between the compressive pulses slight negative pressurepulses may occur. Coherent shock wave energy consists of shock waveshaving the same wavelength or a number of component wavelengths that aremultiples or submultiplies of each other, i.e., that are multiplyrelated. The term sonic waves means periodic bipolar pressure waves,i.e., the pressure at a given point in space sinusoidally oscillatesbetween a pressure higher than ambient and a pressure lower thanambient, so compression and rarification of the fluid modulesalternately occur. The term ultrasonic energy" means sonic wave energyhaving a frequency above the audible range. Coherent sonic wave energyconsists of sonic waves having the same wavelength or a number ofcomponent wavelengths that are multiply related. The term coherentpressure waves is generic to coherent shock waves and coherent sonicwaves.

It has been found that the pressure waves produced by the arrangementsshown herein have the ability to travel far without substantialattenuation, so they can propagate in the intake system of an engine.They also propagate with a surprising degree of three dimensionaluniformity, i.e., they have uniform intensity in the X, Y, and Zdimensions.

Due to the bipolar nature of sonic waves, they produce much higherpressure gradients and, therefore, have greater atomizing power, than acomparable level of shock waves. In contrast to shock waves, thepresence of sonic waves also gives rise to a standing wave patternwithin a confined space. Moreover, due to the highly ordered nature ofcoherent waves, they provide the most effective form of energization ofthe space within the intake system. Hence, the use of coherent sonicwaves is the preferred way to practice the invention.

In practice, coherency is not completely destroyed until the wavelengthsof the pressure wave components deviate by one-quarter wavelength fromtheir prescribed multiple relationship. The same is true with respect tothe relationship between the wavelengths of the pressure waves and thedimensions of the apparatus disclosed below. As a design guide, when theactual dimensional and wavelength relationships are met to within i lOpercent of the prescribed values, the

described results are in fact very effectively achieved. Beyond a ipercent deviation, the eflectiveness of the results drops off but maystill be significant and usable. Further, to the extent that thebeneficial results described herein are still achieved, coherency isalso not destroyed by the presence of some pressure wave energy atcomponent wavelengths that are not multiply related to the principlecomponent wavelengths or by the presence of some random pressure waveenergy, analogous to background noise.

FIGS. 1 and 2 show 'a conventional automobile carburetor 1 in whichgasoline is supplied, from a reservoir (not shown), to booster venturis2, mounted at the inlet ends of venturi shaped barrels 3, 4, throughfuel conduits 5 and fuel inlets 6, and to which air is suppliedgenerally through air inlet 7. Throttle valves 8, 9 control the rate ofsupply of fuel/air mixture to an intake manifold beneath, of which onlya small portion 10 is shown. Gasoline for engine idling is suppliedthrough idle inlets 11 through the lower cylindrical walls 12, 13 ofbarrels 3, 4, respectively, at a rate determined by conventional idlescrews 14.

In each barrel a retainer 15 is mounted wth collar 16 (outside diameter0.625 inches, inside diameter 0.565 inches) around the upper portion ofventuri 2, the collar being notched at 17 (FIG. 7) to admit fuel conduit5. Collar 16 is connected through three legs 18 (each 0.130 inches long)to another collar 19 in which is carried tubular cell 20 (FIGS. 6, 7) inturn containing nozzle 21 (FIGS. 3, 4). Legs 18 extend inwardly toprovide shelves 22 which support cell 20.

Air tube 23, with 60 countersink 24 at its flared inlet end, is solderedto the exterior of collar 19, and extends from the air inlet 7 of thecarburetor to the bottom of collar 19 between two legs 18.

A second cell 25 containing a nozzle 26, respectively identical to cell20 and nozzle 21, is soldered to collar 19 and tube 23. The axes ofnozzles 21 and 26 are parallel to that of tube 23.

The nozzles,-cells, tubes, and retainers in barrels 3 and 4 areidentical, except that they are arranged as mirror images of each other(as seen in FIG. 1).

Each of nozzles 21 and 26 has a cylindrical wall 27 (outside diameter0.346 inches, inside diameter 0.260 inches) open at its outlet endacross 45 countersink 28, which is surrounded by annular flange 31,having an end wall 32. Axial inlet 33 (diameter 0.177 inches) in endwall 34 is concentric with an imaginary circle (diameter 0.226 inches)containing the centers of eight equally spaced holes 35 (each ofdiameter 0.0315 inches). Four radial holes 36 (each of diameter 0.093

inches) in wall 27 have coplanar axes spaced 90.

Length of cell 20 between downstream of wall 39 and upstream face ofcounterbore 41 0.267" Length of nozzle 21 between wall 34 andcountersink 28 0.22! Depth of countersink 28 0.029"

6 Threaded pipe 40 (FIGS. 2, 5) is soldered in the counterbore 41 ofanother cell 42, identical to cell 20,

against the end wall 32 of a nozzle 44, identical to nozzle 21. Theother end of pipe 40 is threaded through hole 45 in the carburetor wallopposite to that receiving idle inlets 11, and into cavity 46 which isopen to the manifold beneath, and communicates with both barrels 3, 4under separatory wall 47. Pipe: 40 is locked in place with nut 48.Bracket 49 is soldered to cell 42 and carries bi-metallic strip 50, atone end of which is mounted valve plug 51 arranged to seal inlet 38 ofcell 42 when strip 50 flexes toward the carburetor from its open(flexed) position of FIG. 5.

In operation, with the engine running, sub-atmospheric pressure in theintake manifold will draw air through inlets 33 and holes 35 and 36 ofnozzles 21 and 26, and out of the nozzles across countersinks 28. Asdescribed in my U.S. Pat. No. 3,554,443, which issued Jan. 12, 1971, andmy US. Pat. No. 3,531,048, which issued Sept. 29, 1970, cells 20 and 25convert a portion of the energy of the fluid stream passing through itinto coherent shock wave energy. Fuel drawn through conduits 5 isatomized and mixes with the energized air passing through nozzles 21 and26, and with additional air entering barrels 3 and 4 through air inlet 7(only a minor portion of the air passing through barrels of 3 and 4having actually passed through the nozzles). Cells 20 and 25 areoriented so the major portion of the shock wave energy they producepropagates in the direction of flow of the carburetor air stream.

When valves 8, 9 are closed, the engine will idle, burning fuel suppliedthrough idle inlets 11. The passage of air through cell 42 and nozzle 44in the manner described above for cells 20 and 25, will atomize idlefuel in mixing therewith in the intake manifold beneath cavity 46,thereby reducing emissions even under idling conditions. Cell 42 isoriented so the major portion of the shock wave energy it producespropagates in the direction of flow of the air stream drawn through pipe40 by the subatmospheric pressure in the intake manifold. When the airstream reaches cavity 46 the shock waves are released and propagate inthe intake manifold in a direction transverse to the carburetor flowstream. The transverse shock wave propagation synergistically reactswith the shock wave propagation in the direction of the carburetor flowstream to enhancethe atomization process. In the embodiment of FIGS.1-7, at low temperatures bimetallic strip 50 will remain unflexed toprevent air flow through cell 42, so that raw fuel will reach the coldengine, as is desirable for engine starting.

The combustible air/fuel mixture, energized in the described manner,passes to the engine for combustion, which has been found to be morecomplete, with less exhaust emission of carbon monoxide and unburnedhydrocarbons, than when the same carburetor is operated under the sameconditions but without the nozzles. For example, a 1969 Oldsmobilecarburetor, with and without the embodiments of FIG. 1, was testedaccording to the federal exhaust emission test set forth in the FederalRegister, Vol. 33, No. 108, Part I (June 4, 1968). The results were anaverage (weighted) decrease in CO (percent of emissions) from 1.2percent to 0.44 percent, and an average (weighted) decrease inhydrocarbons (ppm hexane in emissions) from about 180 ppm to 142 ppm. Atidle, the CO was reduced from about 1 percent or greater to 0.6 percent(cold start) and 0.2 percent (hot start), and hydrocarbons from about180 ppm to 164 ppm (cold start) and 90 ppm (hot start).

FIGS. 8-10 show a conventional automobile carburetor, identical to thatof FIGS. 1 and 2, in which cells 52 are threaded and thereby securedinto the underside of threaded venturis 53, cells 52 being otherwiseidentical to cell and venturis 53 being otherwise identical to venturi2. Cell 52 contains a nozzle 54 identical to nozzle 21. Threaded pipe 55is soldered in the counterbore of cell 56, which is identical to cell 20except that end wall 57 has been thickened to provide a stepped axialinlet formed of an outer inlet hole 58 (diameter 0.l72 inches) inaddition to an inner inlet hole 59 (diameter 0.345 inches), the diameter(0.260 inches) of the axial passage defined by wall 27 beingtherebetween. Cell 56 contains a nozzle 60 identical to nozzle 21 andthreaded pipe 55 extends through a hole into cavity 46, in the samemanner as described for pipe 40. Emission reductions similar to thoseobtained for nozzle 44 of pipe 40 are obtained for nozzle 60.

In operation, fuel through an idle inlet, such as inlet 11 of FIGS. 1,2, is atomized by air entering through cell 56, in the same manner asdescribed above for cell 42. Air from inlet 7 and venturis 53 and fuelfrom inlet 6 both pass through nozzle 54, the fuel being atomized andmixing with additional air from inlet 7. As in the embodiment of FIGS.1-7, the shock waves propagate in the direction of the carburetor flowstream and in the direction transverse thereto to energize thecombustible mixture in the intake system. When tested, utilizing aClayton Dynamometer to measure engine speed and a Lyra Gauge to measuretailpipe emissions, a 1969 Oldsmobile carburetor equipped with cells 52showed an emissions reduction in CO (hot start) from 1.2 percent to 0.45percent, and in hydrocarbons from 180 ppm to 87 ppm.

FIGS. 11-16 show a conventional automobile carburetor identical to thatof FIGS. 1, 2, and 8, and including, additionally, supporting bars 64forming a tripod for supporting threaded slug 65, and a rotatable chokevalve 66. A conventional automobile air filter 67, having a conventionalannular filter element 68, is secured by threaded bolt 69 and wing nut70 on top of bars 64.

Adapter 71 has four cells soldered, at equal spacing, to its peripheralwall 73, each cell 72 being substantially identical with a cell 56,shown in FIG. 10, and including a nozzle 74, identical with nozzle 21.Alternately, four tubular cells 75 are employed, identical to cells 72except that inlet 58 of cell 72 is now located in a separate cap element76, which is press fitted around outer cylindrical wall 77. The interiorwall surface 78 of cap 76 may be slightly spaced from the end wallsurface 79 of wall 77.

Adapter 71 has an axial opening 80 sized to fit slidingly over bolt 69,and four depending, equally spaced, arcuate spacer legs 81, spaced tostraddle supporting bars 64 (FIG. 13), thereby preventing rotation ofadapter 71, and orienting cell 72 to produce air flows interceptingbarrels 3, 4. A nut 82 tightens the adapter against slug 65. The adapterand nut have been rotated up bolt 69 in FIG. 11, so that the pieces maybe more readily identified.

In FIG. 12, a conventional rubber hose oil gallery return line 83 (shownbroken for purposes of illustration only) communicates at one end withcavity 46 in the interior of the carburetor through an opening thereintoand an appropriate pipe (not shown, but similar to pipe 40) and nut 84,and at its opposite end with oil droplets which are returned to thecarburetor for combustion. A cylincrical tube 85 (outer diameter 1 inch,inner diameter 0.870 inches), secured to return line hose 83 byprotuberances 86 and clamps 87, includes an axial inlet 88 (diameter0.312 inches) through inlet cap 89 and an identically sized axial outlet90 through outlet cap 91. Caps 89, 91, are tightly fitted incounterbores 92, 93, respectively, of tube 85 which is swaged about theouter walls of the end caps, as shown in FIG. 12.

Tubular cells 104, 105, are located 180 apart in radial bores 96, 97(diameters 0.5l5 inches), respectively, in tube 85 and each has acylindrical wall 98 (outer diameter 0.531 inches), including a reducedouter diameter (0.518 inches) cylindrical portion 99, press-fitted intobores 96, 97, respectively. Inner wall 100 (diameter 0.43l inches) has acounterbore 101 (diameter 0.470 inch) and nozzles 102, 103 are mountedin cells 104, 105, respectively, with flange 106 (outer diameter 0.468inch) secured in counterbore 101 by swaging of the end of the wallforming counterbore 101. Except for the enlarged diameter of flange 106,nozzles 102, 103 are otherwise identical to nozzle 21. Tubular cells104, each include a stepped inlet coaxial with inlet 33 to nozzles 102,103 and formed on an inner inlet 107 (diameter 0.345 inch) and an outerinlet hole 108 (diameter 0.125 inch).

Tubular cell 109, which is identical with tubular cell 104, and containsa nozzle 110, identical with nozzle 102, is tightly secured in a centralopening 1 1 1 (diameter 0.515 inch) of mounting plate 112, which hasarcuate air passages 113, and is seated in counterbore 92, being spacedtherein from inlet cap 89 by spacer ring 114.

Additional dimensions of the assembly are:

Length of tube 85 1.875" Length of counterbore 92 0.422" Length ofcounterbore 93 0.056" Distance between center of radial bore 96 or 97and outer edge of counterbore 93 0.400

Cylindrical tube 85, with mounted cells 104, 105, and 109, may also beused in combination with embodiments of FIGS. 1-10, in lieu of idle airpipes 40, 55 and cells 42, 56, whereas the air filter-mounted cells 72(or 75) would not preferably be combined with the venturi-mounted cellsof FIGS. 1-10, although they could be combined with the idle air pipesand cells of FIGS. l-l0.

In operation, with the engine running, sub-atmospheric pressure in themanifold will draw a portion of the air drawn through air filter 67 intoinlets 58, 59 of cells 72 or 75, and nozzles 74, out of nozzles 74 tothe carburetor barrels 3, 4, the cells being oriented about adaptor 71to direct the maximum possible air flow to the open throats of barrels3, 4. By placing the cells in air filter or cleaner 67, the air isenergized before it enters carburetor 1 so atomization may have moretime to take place. The energized air flows through and around boosterventuris 2, and the resulting energized air/fuel mixture then flows tothe engine for combustion. A 1969 Chevrolet Impala carburetor showed areduction in emissions from 1.65 percent to 0.35 percent CO and from 230ppm to 120 ppm hydrocarbon (emissions measured on a Lyra Gauge), at mph(measured on a Clayton Dynamometer), when equipped with the cells ofFIG. 1 1.

In addition, where cylindrical tube 85 is also used (or where it is usedin lieu of the air filter-mounted tubular cells), an oil droplet-airmixture, under sub-atmospheric manifold pressure, is drawn throughreturn line 83, and into cylindrical tube 85 through axial inlet 88 andthrough cell 109 and air passages 1 13. At the same time a small amountof atmospheric air is drawn through cells 104, 105 at right angles tothe oil-air flow from inlet 88. The combined flow exits through axialoutlet 90 and is subsequently fed directly to intake manifold 10 throughhole 45 and cavity 46 (FIG. 2) to the engine for burning. As the oildroplet-air mixture flows through tube 85, coherent shock waves areformed and the mixture becomes energized. Due to their coherency, theshock waves travel through return line 83 to intake manifold 10 intactand without substantial attenuation, even with long hose lengths. Whenthe shock waves reach the intake manifold, they are released andpropagate transverse to the direction of the carburetor flow stream withwhich they react in the same manner as the shock waves produced by cell42 in FIG. 2. A 1965 Dodge Polora showed a reduction in emissions from1.15 percent to 0.09 percent CO, and from 150 ppm to 80 ppmhydrocarbon(measured in a Lyra Gauge) at 30 mph (measured on a ClaytonDynamometer), when equipped with the embodiment of FIG. 12.

in all of the above embodiments, the size of the axial inlet to the cellutilized depends, among other considerations, on the weight flow offluid required across the portion of the engine wherethe cells arelocated. For example, where a certain fuel-dispensing air flow isreferred to (as across a booster venturi), larger cell openings areutilized.

In FIG. 12, a shock wave generator housed in tube 85 is disposed in anoil gallery return line, commonly called a PCV (positive crankcaseventilation) return line. FIG. 17 elaborates upon this manner ofintroducr ing pressure wave energy into the intake system of an internalcombustion engine. The engine includes an air cleaner 120, a carburetor121 with a butterfly throttle valve 122, and a crankcase manifold 123.The combustible crankcase emissions produced in the course of theoperation of the engine comprise blowby gases, i.e., incompletelycombusted substances that escape from the combustion cylinders via thepiston rings, and oil particles that become suspended in the air withinthe crankcase manifold. The PCV system returns these crankcase emissionsto the intake system, at the base of the carburetor as shown or at theinlet of the intake manifold, for recombustion in the engine. Clean airis coupled from cleaner 120 by a connecting hose 124 to the crankcasemanifold through an oil filler cap 125. This clean air, represented byarrows 126, mixes with and carries the blowby gases, represented byarrows 127, out of crankcase manifold 123 through a PCV valve 128 asrepresented by arrows 129. PCV valve 128 is coupled to the intake systemby a connecting hose 130, which serves as the PCV, i.e., oil gallery,return line. A pressure wave generator 131 is connected in series withhose 130. The described PCV system is conventional. The onlymodification that is desirable is to provide a spring having a smallerspring constant for PCV valve 128. This enables PCV valve 128 to operatenormally, i.e., to close during idling, deceleration, and cruise, and toopen during acceleration, despite the smaller pressure drops that havefound to exist in the presence of a pressure wave generator. However, itshould be noted that the PCV valve performs an additional function,namely, that of controlling the amount of pressure wave energyintroduced into the intake system. In other embodiments described below,these functions are performed by a valve that is part of an airmanagement system. To install pressure wave generator 131, hose 130 issimply cut and the two ends formed by the out are joined to therespective fittings of pressure wave generator 131.

As the mixture of combustible crankcase emissions and air passes throughpressure wave generator 131, this mixture is energized, thereby becomingdirectly atomized. In addition, the pressure waves propagate into theintake system, as represented by the dots between pressure wavegenerator 131 and carburetor 121, and atomize indirectly the combustiblemixture entering the intake manifold from the carburetor. This indirectatomization is particularly effective when pressure wave generator 131is a sonic wave generator that produces coherent sonic wave energy.Exemplary apparatus is disclosed in application Ser. No. 1 1 1,995. Insuch case, the coherent sonic waves propagate into the intake system inan orderly fashion transverse to the carburetor flow stream to form astanding wave veil across the outlet of carburetor 121 through which thecombustible mixture formed in the carburetor must pass before enteringthe intake manifold. The standing waves also extend into the intakemanifold. The result is that the combustible mixture from the carburetoris finely atomized: Although a shock wave generator is also an efiectivepressure wave generator, it is not as efficient as a coherent sonic wavegenerator. After the transversely propagating shock waves entercarburetor 121, they are reflected haphazardly from the firstobstruction in their path and then dissipate. Thus, their range andeffectiveness are substantially less than coherent sonic waves.Different configurations of shock wave generators are disposed in returnlines in applications Ser. No. 13,977 and Ser. No. 17,484, thedisclosures of which are incorporated herein by reference at this pointof the present specification.

In FIG. 18, coherent sonic wave energy is introduced into the intakesystem of an internal combustion engine in several different ways. Anair cleaner 135 is mounted above a carburetor 136 in communication withits inlet. Carburetor 136 is mounted on an intake manifold 137. All theair drawn into carburetor 136 through air cleaner 135 is processed by asonic wave generator disppsed inside the filter element of air cleaner135. This sonic wave generator, not illustrated in FIG. 18, is describedbelow in connection with FIG. 24. For the purpose of illustration,carburetor 136 is represented as a dual carburetor having two barrelsdefined by constricted regions 138 and 139 and two butterfly throttlevalves 140 and 141 that control the extent to which carburetor outletorifices 142 and 143 are open. A flat metal plate 144 having openings145 and 146 is clamped between carburetor 136 and manifold 137 bycarburetor mounting fasteners 147 and 148. A schematically representedsonic wave generator 149, discussed in detail in connection with FIG.19, is attached to plate 144, to introduce coherent sonic wave energy atthe interface between carburetor 136 and intake manifold 137. Manifold137 has inlet orifices 150 and 151. Openings 145 and 146 of plate 144are the same size and shape as inlet orifices 150 and 151, respectively,of intake manifold 137, as depicted in FIG. 18. As further depicted inFIG. 18, orifice 142, opening 145, and orifice 150 are all axiallyaligned with each other, and orifice 143, opening 146, and orifice 151are all axially aligned with each other to present unobstructed passagesfor the combustible mixture formed in carburetor 136. Manifold 137 hasrunners such as those designated 152 and 153 that connect manifold 137with the combustion cylinders of the engine such as those designated 154and 155. Cylinder 154 is shown during its intake stroke in which anintake valve 156 is open, an exhaust valve 157 is closed, and a pistonrod 158 is drawing a piston 159 downward. Cylinder 155 is shown duringits exhaust stroke in which an intake valve 160 is closed, an exhaustvalve 161 is open, and a piston rod 162 is pushing a piston 163 upward.An exhaust manifold has runners such as those designated 164 and 165that communicate with cylinders 154 and 155, respectively, throughexhaust valves 157 and 161, respectively. A schematically representedsonic wave generator 133 is coupled by an air management valve 134 tointake manifold 137 at a point central to the intake valves of all thecombustion cylinders.

All the described components are conventional parts of an internalcombustion engine except from the sonic wave generator disposed in aircleaner 135, plate 144, sonic wave generator 149, and sonic wavegenerator 133. First, the effect of sonic wave generator 149 will bedescribed, assuming for that purpose the sonic wave generator in aircleaner 135 and sonic wave generator 133 are not present. Sonic wavegenerator 149 produces coherent sonic wave energy that initiallypropagates across openings 145 and 146 in a direction parallel to theplane of plate 144, i.e., horizontally, as viewed in FIG. 18, to formstanding waves across openings 145 and 146, the sonic wave energyproduced by sonic wave generator 149 propagates from openings 145 and146 downstream into manifold 137 and enters the combustioncylinders'including cylinders 154 and 155 each time the respectiveintake valves are opened. Consequently, standing waves, represented bythe dots in FIG. 18, are also formed in manifold 137 and in thecombustion cylinders. As represented by the dots in cylinder 155 andrunners 164 and 165, the standing waves even survive the combustionprocess to some extent and are pushed into the exhaust manifold duringthe exhaust stroke. To a lesser extent, the sonic wave energy alsopropagates upstream into carburetor 136 to form attenuated standingwaves, as depicted by the dots in the interior of carburetor 136. Thehigher concentration of dots in manifold 137 and combustion cylinders154 and 155 than in carburetor 136 signifies the standing sonic wavesare much stronger in the former than in the latter.

The standing sonic waves intercept the combustible mixture as its entersinlet orifices 150 and 151 of manifold 137 to atomize the combustiblemixture into a more finely suspended state, which is maintainedthroughout manifold 137 and the combustion cylinders by the standingwaves formed therein. The high degree of atomization brought about bythe standing sonic waves permits a more complete and efficient burningof the combustible mixture in the engine. As a result, a lower level ofcarbon monoxide and hydrocarbons is emitted by the engine, and morecarbon dioxide is produced. The reduction in the hydrocarbon and carbonmonoxide emissions is much greater than would be achieved simplyintroducing the same amount of additional air into the intake system inthe absence of coherent sonic waves. (The same is true to a lesserextent in the case of coherent shock wave energy, vis-avis, theadditional air involved). In fact, some ways of introduction of thesonic wave energy involve no additional air, e.g., a sonic wavegenerator in air cleaner or a sonic wave generator without transversecells in the PCV line. As used in this specification, the term enoughcoherent pressure wave energy to atomize more finely the combustiblemixture is to be determined by the resulting reduction of hydrocarbonand carbon monoxide emissions the reduction is noticeably greater thanthat achieved by the same amount of additional air in the absence ofcoherent pressure waves.

It is an established fact that the level of the oxides of nitrogenproduced in an internal combustion engine is directly related to theaverage heat in the combustion cylinders, i.e., the heat in the cylinderaveraged over the entire four interval or stroke cycle. In addition tothe described reduction in the level of carbon monoxide andhydrocarbon'emissions, the level of the oxides of nitrogen dropsmarkedly. It is believed the reduction in the oxides of nitrogen isattributable to two effects exercised on the operation of the engine bythe standing sonic waves. First, the standing sonic waves prevent theformation of fuel droplets on the interior walls of manifold 137 and thecylinders. The absence of fuel droplets on the interior walls of thecylinders is particularly important because it prevents the combustionprocess from taking place in physical contact with these walls.Consequently, the interior walls of the cylinders are not permitted tobecome as hot during the combustion interval of the cycle. Second, thestanding sonic waves improve the rate of heat transfer out of thecylinders through its walls after the combustion interval of the cyclebecause of increased heat convection to the walls. In summary, the highdegree of atomization of the combustible mixture in the cylinders causesmore heat to be generated during the combustion interval of the cycle,thereby permitting higher engine efficiency; the isolation of thecombustible mixture from the cylinder walls before and during thecombustion interval of each cycle causes the cylinder walls to remaincooler during the combustion interval, although more heat is generated;and the improved heat transfer out of the cylinders through its wallscauses the heat generated during the combustion interval to bedissipated more quickly after combustion. Although a higher peak valueof heat is generated during the combustion interval, the average heat inthe cylinders is less. A reduction of the oxides of nitrogen istherefore compatible with a reduction of the carbon monoxide andhydrocarbon emissions, improved engine performance, and less gasolineconsumption, because the heat present in the cylinders is more highlyconcentrated in the time interval of the cylinder cycle where it can beutilized to drive the pistons.

It is also believed the reduction of the oxides of nitrogen may beattributable in part to magnetic fields associated with the coherentsonic waves in some manner not yet fully understood. These magneticfields may actually inhibit the chemical combination of oxygeii andnitrogen.

The presence of the sonic wave generator in air cleaner 135 and sonicwave generator 133 synergistically enhances the effect of sonic wavegenerator 149 described above. The sonic wave generator in air cleaner135, in introducing coherent sonic wae energy, energizes the entirecarburetor flow stream to atomize the combustible mixture before itreaches plate 144 and to enhance the atomizing action of thetransversely propagating coherent sonic wave energy introduced at plate144. Sonic wave generator 133, which is preferably activated only duringengine modes where very large amounts of coherent sonic wave energy isrequired, strengthens the standing waves in intake manifold 137 and thecombustion cylinders. Air management valve 134 could be a vacuumactuated valve that opens during acceleration and remains closed exceptfor a bleed orifice during the other engine modes, as described below inconnection with FIG. 27 or an elaborately controlled valve, as describedbelow in connection with FIGS. 28, 30 and 32.

In general, it has been found that the more coherent sonic wave energythat is introduced into the intake system, the better are the results,assuming that the additional air introduced into the intake system islimited so as not to impair these results. There are three degrees ofimprovement in the level of the oxides of nitrogen achieved by theinvention, depending upon the amount of coherent sonic wave energyintroduced. In the first degree, when a little coherent sonic waveenergy is introduced, the level of the oxides of nitrogen increases asthe level of hydrocarbon and carbon monoxide emissions decreases, butthis increase of the oxides of nitrogen is noticeably less than theincrease of the oxides of nitrogen that occurs when the same decrease ofthe hydrocarbon and carbon monoxide level is brought about by increasingthe air-to-fuel ratio. In the second degree, when more coherent sonicwave energy is introduced, the level of the oxides of nitrogen remainssubstantially the same as the level of hydrocarbon and carbon monoxideemissions decreases. In the third degree, when still more coherent sonicwave energy is introduced, the level of the oxides of nitrogen decreasesas the level of hydrocarbon and carbon monoxide emissions decreases. Asused in this specification, the term enough coherent sonic wave energyto inhibit the production of the oxides of nitrogen embraces all threedegrees of improvement. As mentioned above, all three degrees ofimprovement provide a much greater reduction in the hydrocarbon andcarbon monoxide emissions than would be achieved simply by introducingthe same amount of additional air into the intake system in the absenceof coherent sonic waves.-

FIG. 19 depicts plate 144 and sonic wave generator 149 in detail for thepurpose of illustrating one embodiment that the equipment for generatingthe coherent sonic wave energy can take. It is to be understood,however, that as far as this aspect of the present invention isconcerned, the particular configuration of the sonic wave generator isnot essential. Any other type of sonic wave generator capable ofproducing coherent sonic wave energy that will form standing sonic wavesin an enclosed region can be used to practice this aspect of theinvention. In fact, the partiuclar sonic wave generator disclosed inFIG. 2 is itself the subject of another copending patent application ofmine, Ser. No. 85,911, filed Nov. 2, 1970. Sonic wave generator 149comprises a shock wave generator 167, a resonant cavity 168, and aconduit 169 coupling shock wave generator 167 to cavity 168.

To install plate 144 in the engine of FIG. 18, the following steps aretaken: fasteners 147 and 148 are opened; carburetor 136 is lifted fromits mounting surface on manifold 137; a gasket and gasket sealer areplaced on the mounting surface of manifold 137; plate 144 is placed ongasket 170; a gasket 171 and gasket sealer are placed on plate 144;carburetor 136 is placed on gasket 171; and fasteners 147 and 148 aretightened down to secure the whole assembly, as shown in FIG. 18. Gasket170 is preferably a conventional automotive gasket, gasket 171 ispreferably a gasket that is permanently bonded to the surface plate 144,and gaskets 170 and 171 both correspond in size and shape to plate 144,including openings 145 and 146. Thus, gasket 171 covers the otheropenings in the surface of plate 144 shown in FIG. 19.

Shock wave generator 167 comprises a shock wave generating unit 172 anda shock wave generating unit 173 connected in parallel between an airmanagement valve 174 and a coupling 175 by Y-connections 176 and 177.Valve 174, which communicates with the atmosphere, is a conventional,such as a standard PCV valve, which normally restricts the flow of airto a low bleed value. When the pressure drop from the atmosphere toconnection 176 drops below a minimum value, valve 174 opens to supply a:much higher flow of air from the atmosphere to units 172 and 173. Thisminimum pressure drop represents the transition from idle toacceleration. Valve 174, which could be the same type valve used in theconventional PCV system, serves to prevent too much air flow duringidle, cruise, and deceleration, and to supply enough energy to meet thedemands of the mode of engine operation. By way of example, the PCVvalve disclosed on page 5 of Automotive Smog Control Manual, by HaroldT. Glenn, Cowles Education Corporation, New York, N.Y., 1968, could beemployed for valve 174. Preferably, units 172 and 173 each comprise apair of supersonic flow generating cells in tandem with each other, asdisclosed in my copending application Ser. No. 13,977, filed Feb. 25,1970, the disclosure of which is incorporated herein by reference. Theindividual cells of units 172 and 173 preferably each have thedimensions and hole diameters specified in my US. Pat. No. 3,554,443,the disclosure of which is incorporated herein by reference. The onlyexception is that it is preferable to make the inlet diameter of thecell housing equal to the axial inlet diameter of the nozzle instead oflarger.

For the purpose of discussion, it is assumed that the individual cellsof units 172 and 173 each have the dimensions and hole diametersspecified in US. Pat. No. 3,554,443. In such case, for the temperatureand pressure conditions normally encountered in automative applications,the subsonic air drawn into units 172 and 173 is converted to asupersonic air stream that produces coherent shock waves having awavelength in the range ofO. 170 inches to 0.194 inches as the principleenergy component, depending on the prevailing temperature and pressureconditions. In addition to the principle component, the cells of units172 and 173 also produce other pressure wave components discussed in US.Pat. No. 3,554,443, which have wavelengths that are multiples and/orsubmultiples of the wavelength of the principle energy component. Infact, it is felt the presence of a plurality of multiply related shockwave wavelengths enhances the coherency of the shock wave and sonic waveenergy, i.e., increases the ability of the energy to travel longdistances and to atomize the combustible mixture.

Plate 144 has mounting holes 178, 179, 180, and 181, through which themanifold-carburetor fasteners pass. In addition to cavity 168, whichcommunicates at its ends with openings 145 and 146, there are alsoformed in plate 144, resonant cavities 182, 183, and 184, whichcommunicate with opening 145, and resonant cavities 185, 186, and 187,which communicate with opening 146. As illustrated in FIG. 19, cavities168, 182, 183, and 184 are spaced around opening 145 at 90 intervals,and cavities 168, 185, 186, and 187 are spaced around opening 146 at 90intervals. Gasket 171 is bonded to the surface of plate 144, designated188, so that gasket 171 is pressed into the areas of cavities 168, 182,183, 184, 185, 186, and 187, and conduit 169 that open to surface 188.The Z dimension depicted in FIG. 19, i.e., the height of cavities 168,182, 183, 184, 185, 186, and 187 and conduit 169, is measured withgasket 171 in place, i.e., it is the distance from the surface of gasket171 pressed into the openings to the opposite surface formed by plate144 itself. The height Z, the depth X, and the width Y of cavities 182,183, 184, 185, 186, and 187, the height Z and the depth X of cavity 168,and the width Y and the height Z of conduit 169 are all preferably equalto the wavelength of the principle energy component produced by units172 and 173, e.g., 0.172 inches. The width Y of cavity 168 is notimportant, it being determined only by the spacing between openings 145and 146, which are in turn determined by the spacing between inletorifices 150 and 151. In some cases, it may be advantageous to changethe X, Y and/or Z dimensions of cavities 182, 183, 184, 185, 186, and187, the X and/or Y dimension of conduit 169, or the X and/or Zdimensions of cavity 168 to equal some multiple or submultiple of thewavelength of the principle energy component, depending on the air flowthat can be tolerated. Conduit 169 could also have a circular crosssection with a diameter Y instead of a square one. In general, the X, Y,and Z dimensions of the cavities and conduit, and the wavelength orwavelengths of the shock wave energy are all multiply related. (Themultiple may be 1.)

The substmospheric pressure created in manifold 137 by the operation ofthe engine establishes between valve 174 and resonant cavity 168 apressure drop that draws air through units 172 and 173, therebyproducing shock wave energy. Thus, connections 176 and 177 constitute afluid line connecting the atmosphere to the interface betwweencarburetor 136 and intake manifold 137 via plate 144, shock wavegenerator 167 is disposed in this fluid line to convert a portion of theenergy of the air drawn from the atmosphere into pressure waves thatpropagate into the intake system, and air management valve 174 isdisposed in this fluid line to control the flow rate of air from theatmosphere responsive to the mode of engine operation. The shock waveenergy produced by units 172 and 173 is coupled through conduit 169 toresonant cavity 168 where this shock wave energy is converted tocoherent sonic wave energy by resonant action. The sonic wave energypropagates outwardly from the ends of cavity 168 into openings and 146in the direction of the plane of plate 144 to form across openings 145and 146 standing sonic waves. part of this sonic wave energy isintercepted by resonant cavities 182, 183, and 184, and resonantcavities 185, 186, and 187 to further enhance the intensity anduniformity of the stnading sonic waves formed across openings 145 and146. The sonic energy then propagates from openings 145 and 146 in adirection transverse to the plane of plate 144, thereby also forming inmanifold 137 and the combustion cylinders standing sonic waves. Thevolume of air introduced into the intake system by sonic wave generator149 is small, e.g., below 10 percent of the total air intake, so thecombustible mixture from the carburetor is not made too lean by theintroduction of the sonic wave energy.

In the course of engine operation, the pressure drop from the atmosphereto intake manifold 137 varies substantially and the pressure dropbecomes quite small during acceleration. Even with small pressure drops,sonic wave generator 149 is capable of producing coherent sonic waveenergy of high intensity. Further, as described in 1.1.5. Pat. Nos.3,554,443 and 3,531,048, the cells comprising units 172 and 173 are selfcompensating for pressure changes, continuing to produce shock waves ofsubstantially the same wavelength, i.e., within a i 10 percent range, asthe pressure drop varies.

Thus, the dimensions X, Y, and Z, after they are once matched to thedimensions of the cells, remain suitable and effective for all operatingconditons of the engine.

In FIG. 20 is shown an alternative embodiment of the shock wavegenerator 167 and plate 144. The particular shape of the outer perimeterof plate 144 is dictated by the shape of the mounting flanges at theinterface between carburetor 136 and intake manifold 137. The samereference numerals are employed in FIG. 20 to designate elementscorresponding to the elements of the embodiment of FIG. 19. Thecomponents of shock wave generator 167 are housed in a cylindrical bycouplings 191 and 192, respectively, to units 172 and 173. At the otherend, valves 174a and 174b are connected to couplings 193 and 194,respectively. Rubber hoses 195 and 196 connect couplings 193 and 194,respectively, to couplings 197 and 198, respectively, at plate 144. Afine mesh 199 covers the end of cannister 190 opposite couplings 193 and194 to prevent foreign matter from entering. The vacuum of the enginedraws air through mesh 199 into units 172 and 173 and through valves174a and 174b and hoses 195 and 196 to plate 144.

In contrast to the embodiment of FIG. 19, valves 174a and 174b aredisposed downstream of units 172 and 173. As a result of thisrearrangement, it has been found that the snap-action valves open andclose more reliably in response to changes in the mode of operation ofthe engine and that the level of the sonic wave energy introduced intothe intake system is enhanced somewhanlt is believed that the plug ofthe valve amplifies to some extent the shock waves emanating from theshock wave generating unit.

The packaging arrangement of FIG. is a particularly important practicalaspect of the installation of the equipment in the engine space.Cannister 190 can be mounted any place under the hood where spacepermits and coupled by hoses 195 and 196 to plate 144, which is disposedat the carburetor-manifold interface. As long as the diameter of hoses195 and 196 and the wavelength of shock wave energy are multiplyrelated, the attenuation in hoses 195 and 196 does not significantlyaffect the results.

In FIG. 20, conduits 169a and 16% replace the upstream portion ofconduit 169 and a transverse conduit 200 couples conduits 169a and 169bto the downstream portion of conduit 169 and to cavities 182 and 187.Conduits 169a and 169b ae connected to hoses 195 and 196, respectively,by couplings 197 and 198. Conduits 169a and 169b have round crosssections with a diameter preferably equal to the X, Y, and Z dimensionsof the cavities. The distance U along conduit 200 between conduits 169aand 169 and the distance V along conduit 200 between conduits 169b and169 are each a whole number of wavelengths of the principle energycomponent, e.g., 0.172 inches. In other words, the Hand V dimensions areboth multiples of the X, Y, and Z dimensions. It has been found thatsuch dimensioning tends to make the flow rate through the sonic wavegenerator directly dependent upon the absolute pressure in the intakemanifold. As a result, when valves 174a and l74b open and closeresponsive to pressure changes in the course of engine operation, thetransition in the flow rate into the intake systemthrough the sonic wavegenerator is made more gradual than the sudden change in the orificearea of the valves alone would dictate. Cavities 182, 183, 184, 185, 186, and 187 are effectively cubicle, i.e., cubicle to within: 10 percentof the nominal dimensions, 1

although their back surfaces are actually rounded to facilitate themachining operation required to form them.

FIGS. 21 and 22 show a sonic wave generator through which the flow rateis even more strongly dependent upon the absolute pressure in the intakemanifold. A network 205 of channels having a rectangular, preferablysquare, cross section is formed by grooves on one side of a metal plate206 and the adjacent side of a metal plate 207, which is clamped toplate 206 by fasteners 208, 209, 210, and 211. Network 205, which isconstructed in clamped plates 206 and 207 only for ease of prototypefabrication, could be formed in any other type of convenient structure.Network 205 comprises a circular channel 212 that circumscribes anequilateral triangular channel 213, channels 214, 215, and 216 thatconnect circular channel 212 with the comers of triangular channel 213,and channels 217, 218, and 219 that connect the midpoints of the sidesof triangular channel 213 with a transverse central passage 220.

This sonic wave generator is adapted for placement in the PCV returnline as pressure wave generator 131 in FIG. 17. It could also be used assonic wave generator 133 FIG. 18) or substituted for shock wavegenerator 167. In a one piece construction with plates 206 and 207 arean air management valve 221 and a supersonic flow generating cell 222,which is identical to one of the supersonic flow generating cellsreferred to in connection with FIG. 19. Valve 221 replaces PCV valve 128(FIG. 17), which is removed permanently when the sonic wave generator isinstalled. One end of central passage 220 is connected to valve 221 andthe other end of central passage 220 adjoins cell 222, which is pressfitted in a counterbore formed in plate 206. A bleed conduit 225connects circular channel 212 to the atmospheric pressure external ofplate 206. The combustible emissions from the crankcase manifold flowthrough hose to valve 221, as represented by an arrow 223 and from cell222 through hose 130 to the intake system, as represented by an arrow224. As represnted by an arrow 226, a small amount of air from theatmosphere is drawn into conduit 225 and mixes with the combustiblemixture returned from the crankcase manifold.

The sides of .the cross section of the channels, i.e., the Y and Zdimensions (FIG. 22) and the distances between the junctions of circularchannel 212 with connecting channels 214, 215, and 216, and thejunctions of triangular channel 213 with connecting channels 217, 218,and 219, i.e., the R, R',S, S, T, and T. dimensions (FIG. 21) are allmultiply related. As a result of this dimensional interrelationship, theenergy of the fluid stream flowing through valve 221 is converted intocoherent sonic wave energy having a wavelength equal to the Y and Zdimension, e.g., 0.172 inches. The diameter of bleed conduit 225 is alsomul' tiply related; e.g., if the Y and Z dimensions are both 0.]72inches, the diameter of bleed conduit 225 is 0.086 inches. As a resultof this dimensional relationship, the small stream of air flowingthrough bleed conduit 225 serves to enhance the imtnesity of the sonicwave energy. The dimensions of cell 222 match the X and Y dimension ofnetwork 205; e.g., if the X and Y dimensions are both 0.172 inches, cell222 has the dimensions specified in US. Pat. No. 3,554,443, with theexemption pointed out in connection with the cells of units Y172 and 173(FIG. 19). As a result of this dimensional interrelationship, cell 222also serves to enhance the intensity of the sonic wave energy generatedin network 205.

In FIG. 23 a modifiction of the sonic wave generator of FIGS. 21 and 22is shown. In partiucular, valve 221

1. In an internal combustion engine having one or more combustion chambers, a carburetor for mixing air and fuel to form a combustible mixture, an intake manifold for coupling the combustible mixture from the carburetor to the combustion chamber, and an interface between the carburetor and the intake manifold, the improvement comprising: a source of fluid at a higher pressure than the intake manifold; a fluid line connecting the source to the interface between the carburetor and the intake manifold to draw fluid from the source through the fuid line into the intake manifold without passing through the carburetor; means in the fluid line for converting a portion of the energy of the fluid drawn from the source into pressure waves that propagate with the fluid into the intake system; and valve means in the fluid line responsive to the mode of engine operation for controlling the flow rate of the fluid from the source drawn into the intake system through the entrance.
 2. The combination of claim 1, in which the source of fluid is air at atmospheric pressure.
 3. The combination of claim 2, in which the converting means comprises: means for generating shock waves having an intensity related to the flow rate established by the controlling means; a resonator dimensioned relative to the wavelength of the shock waves to convert the shock waves to sonic waves; and means for coupling the shock waves to the resonator to covert them to sonic waves.
 4. The combination of claim 3, in which the resonator is located at the interface between the carburetor and the intake manifold, the generating and controlling means are remotely located from the interface, and the coupling means comprises a conduit having a cross-sectional dimension multiply related to the wavelength of the shock waves.
 5. The combination of claim 3, in which the resonator is formed in a flat plate interposed between the carburetor and the intake manifold at the interface.
 6. The combination of claim 5, in which the means for generating shock waves is a shock wave generating cell comprising: a cylindrical nozzle body open at its end adjacent to the coupling means, bounded along its length by a side wall, and bounded at its other end by an end wall having a large center hole; a plurality of smaller equally spaced peripheral holes disposed about the center hole in the end wall in oppositely arranged pairs; a plurality of pairs of oppositely disposed throat plane stabilizing holes lying in a common plane in the side wall near the open end of the body; and a cylindrical cover enclosing the nozzle body to form an annular region surrounding the cylindrical side wall of the nozzle body, the cell cover completely enclosing the nozzle body except for its open end and an opening at its upstream end that communicates with the holes of the nozzle body.
 7. The combination of claim 1, in which the converting means comprises a pressure wave generator through which the fluid drawn from the source passes to generate pressure waves, the flow rate through the pressure wave generator being in part directly related to the absolute pressure in the intake system.
 8. The combination of claim 1, in which the controlling means comprises a vacuum-operated, valve through which the drawn fluid passes, the valve opening above a predetermined absolute pressure in the intake system representing acceleration, closing below the predetermined absolute pressure, and having a bleed orifice through which a small amount of the fluid flows when it is closed.
 9. The combination of claim 1, in which the carburetor has a main air flow passage from the atmosphere, the combination additionally comprising means for energizing with pressure wave energy all the air passing from the atmosphere through the main air passage.
 10. The combination of claim 1, in which the engine additionally has a crankcase manifold containing combustible crankcase emissions, the source of fluid is the crankcase manifold, the fluid line is a PCV line connecting the crankcase manifold to the interface between the carburetor and the intake manifold, and the valve means is a PCV valve. 